create

Create Local Repo in Rocky Linux 8

January 30, 2022 by Ulysses

How to create a local repo in Rocky Linux 8.

Install nginx. Enable service.

dnf install nginx
systemctl enable nginx --now
systemctl status nginx

Create repo.

dnf repolist
dnf install createrepo yum-utils
mkdir /usr/share/nginx/html/repos
mkdir -p /usr/share/nginx/html/repos/{baseos,appstream}

Sync repos.

dnf reposync -g --delete -p /usr/share/nginx/html/repos/ --repoid=baseos --newest-only --download-metadata
dnf reposync -g --delete -p /usr/share/nginx/html/repos/ --repoid=appstream --newest-only --download-metadata
createrepo /usr/share/nginx/html/repos/baseos/
createrepo /usr/share/nginx/html/repos/appstream/

Create cron to sync repos daily. Create file called /etc/cron.daily/update-localrepos

#!/bin/bash
/bin/dnf reposync -g --delete -p /usr/share/nginx/html/repos/ --repoid=baseos --newest-only --download-metadata
/bin/dnf reposync -g --delete -p /usr/share/nginx/html/repos/ --repoid=appstream --newest-only --download-metadata
/usr/bin/createrepo /usr/share/nginx/html/repos/baseos/
/usr/bin/createrepo /usr/share/nginx/html/repos/appstream/

Create a file called /etc/nginx/conf.d/repos.conf.

server {
        listen   80;
        server_name  reposerver.example.com;
        root   /usr/share/nginx/html/repos;
	index index.html; 
	location / {
                autoindex on;
        }
}

Restart nginx.

systemctl restart nginx

Configure firewall and SELinux.

firewall-cmd --zone=public --permanent --add-service=http
firewall-cmd --reload
getenforce
chcon -Rt httpd_sys_content_t /usr/share/nginx/html/repos/

Move existing repos to /tmp.

mv /etc/yum.repos.d/*.repo /tmp/

Create a new repo called /etc/yum.repos.d/localrepo.repo

[localrepo-base]
name=RockyLinux Base
baseurl=http://reposerver.example.com/baseos/
gpgcheck=0
enabled=1
[localrepo-appstream]
name=RockyLinux Base
baseurl=http://reposerver.example.com/appstream/
gpgcheck=0
enabled=1

Clean cache and check repolist.

dnf clean all 
dnf repolist

Edit /etc/hosts and add reposerver.example.com. Add it to other hosts.

echo "10.10.10.10        reposerver.example.com     reposerver" >> /etc/hosts

Finally, run yum install against the local repo. Installing lvm in this example.

yum install lvm2

AWS Terraform Security Group

January 4, 2022 by Ulysses

How to create AWS security groups using Terraform.

resource "aws_security_group" "my-security-group" {
  name        = "my-security-group"
  description = "allow ports"
  vpc_id      = aws_vpc.my-vpc.id
 
  ingress {
    description = "ping"
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
  ingress {
    description = "http"
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
  ingress {
    description = "https"
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "ALL"
    cidr_blocks = ["0.0.0.0/0"]
  }
  tags = {
    Name = "my-security-group"
  }
}

AWS CloudFormation Security Group

December 29, 2021 by Ulysses

AWS CloudFormation to create security groups. Includes self-refencing ingress and egress rules.

AWSTemplateFormatVersion: '2010-09-09'
Description: my-security-groups
######################################
Parameters:
  EC2Vpc:
    ConstraintDescription: Must be a valid VpcId
    Description: Select the VPC to use
    Type: AWS::EC2::VPC::Id
##############################################################################
Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
    - Label:
        default: VPC
      Parameters:
      - EC2Vpc
##############################################################################
Resources:
  EC2InstanceSecurityGroup1:
    Type: AWS::EC2::SecurityGroup
    Properties:
      VpcId: 
        Ref: EC2Vpc
      GroupDescription: my-security-group-1
      GroupName: my-security-group-1
      SecurityGroupIngress:
        - {CidrIp: 10.0.0.0/8,                        IpProtocol: tcp,  FromPort: '80',      ToPort: '80',    Description: 'HTTP'}  
      SecurityGroupEgress:
        - {CidrIp: 10.0.0.0/8,                        IpProtocol: udp,  FromPort: '123',     ToPort: '123',   Description: 'NTP'}  
        - {CidrIp: 10.0.0.0/8,                        IpProtocol: tcp,  FromPort: '53',      ToPort: '53',    Description: 'DNS'}
      Tags:
        - {Key: Name,         Value: 'my-security-group-1'}
  EC2InstanceSecurityGroup2:
    Type: AWS::EC2::SecurityGroup
    Properties:
      VpcId: 
        Ref: EC2Vpc
      GroupDescription: my-security-group-2
      GroupName: my-security-group-2
      SecurityGroupIngress:
        - {CidrIp: 0.0.0.0/0,                        IpProtocol: tcp,  FromPort: '443',     ToPort: '443',   Description: 'HTTP'}  
        - {CidrIp: 0.0.0.0/0,                        IpProtocol: icmp, FromPort: '-1',      ToPort: '-1',    Description: 'ICMP ping'}
      SecurityGroupEgress:
        - {CidrIp: 10.0.0.0/8,                       IpProtocol: udp,  FromPort: '123',     ToPort: '123',   Description: 'NTP'}  
        - {CidrIp: 10.0.0.0/8,                       IpProtocol: tcp,  FromPort: '53',      ToPort: '53',    Description: 'DNS'}
        - {CidrIp: 0.0.0.0/0,                        IpProtocol: icmp, FromPort: '-1',      ToPort: '-1',    Description: 'ICMP ping'}
      Tags:
        - {Key: Name,         Value: 'my-security-group-2'}
  MyIngressSelfAll:
    Type: AWS::EC2::SecurityGroupIngress
    Properties:
      GroupId: !Ref EC2InstanceSecurityGroup2
      SourceSecurityGroupId: !GetAtt EC2InstanceSecurityGroup2.GroupId
      IpProtocol: -1
      FromPort: 0
      ToPort: 65535
  MyEgressSelfAll:
    Type: AWS::EC2::SecurityGroupEgress
    Properties: 
      GroupId: !Ref EC2InstanceSecurityGroup2
      DestinationSecurityGroupId: !GetAtt EC2InstanceSecurityGroup2.GroupId
      IpProtocol: -1 
      FromPort: 0
      ToPort: 65535
##############################################################################
Outputs:
  SecurityGroupId:
    Description: The Security Group that was created
    Value: {Ref: EC2InstanceSecurityGroup1}
    Value: {Ref: EC2InstanceSecurityGroup2}
  StackName:
    Description: Name of this stack for Fn::ImportValue use by children of top level stack
    Value: {Ref: 'AWS::StackName'}

AWSTemplateFormatVersion: '2010-09-09' Description: my-security-groups ###################################### Parameters: EC2Vpc: ConstraintDescription: Must be a valid VpcId Description: Select the VPC to use Type: AWS::EC2::VPC::Id ############################################################################## Metadata: AWS::CloudFormation::Interface: ParameterGroups: - Label: default: VPC Parameters: - EC2Vpc ############################################################################## Resources: EC2InstanceSecurityGroup1: Type: AWS::EC2::SecurityGroup Properties: VpcId: Ref: EC2Vpc GroupDescription: my-security-group-1 GroupName: my-security-group-1 SecurityGroupIngress: - {CidrIp: 10.0.0.0/8, IpProtocol: tcp, FromPort: '80', ToPort: '80', Description: 'HTTP'} SecurityGroupEgress: - {CidrIp: 10.0.0.0/8, IpProtocol: udp, FromPort: '123', ToPort: '123', Description: 'NTP'} - {CidrIp: 10.0.0.0/8, IpProtocol: tcp, FromPort: '53', ToPort: '53', Description: 'DNS'} Tags: - {Key: Name, Value: 'my-security-group-1'} EC2InstanceSecurityGroup2: Type: AWS::EC2::SecurityGroup Properties: VpcId: Ref: EC2Vpc GroupDescription: my-security-group-2 GroupName: my-security-group-2 SecurityGroupIngress: - {CidrIp: 0.0.0.0/0, IpProtocol: tcp, FromPort: '443', ToPort: '443', Description: 'HTTP'} - {CidrIp: 0.0.0.0/0, IpProtocol: icmp, FromPort: '-1', ToPort: '-1', Description: 'ICMP ping'} SecurityGroupEgress: - {CidrIp: 10.0.0.0/8, IpProtocol: udp, FromPort: '123', ToPort: '123', Description: 'NTP'} - {CidrIp: 10.0.0.0/8, IpProtocol: tcp, FromPort: '53', ToPort: '53', Description: 'DNS'} - {CidrIp: 0.0.0.0/0, IpProtocol: icmp, FromPort: '-1', ToPort: '-1', Description: 'ICMP ping'} Tags: - {Key: Name, Value: 'my-security-group-2'} MyIngressSelfAll: Type: AWS::EC2::SecurityGroupIngress Properties: GroupId: !Ref EC2InstanceSecurityGroup2 SourceSecurityGroupId: !GetAtt EC2InstanceSecurityGroup2.GroupId IpProtocol: -1 FromPort: 0 ToPort: 65535 MyEgressSelfAll: Type: AWS::EC2::SecurityGroupEgress Properties: GroupId: !Ref EC2InstanceSecurityGroup2 DestinationSecurityGroupId: !GetAtt EC2InstanceSecurityGroup2.GroupId IpProtocol: -1 FromPort: 0 ToPort: 65535 ############################################################################## Outputs: SecurityGroupId: Description: The Security Group that was created Value: {Ref: EC2InstanceSecurityGroup1} Value: {Ref: EC2InstanceSecurityGroup2} StackName: Description: Name of this stack for Fn::ImportValue use by children of top level stack Value: {Ref: 'AWS::StackName'}

Create AWS VPC using Terraform

December 21, 2021 by Ulysses

Creating a VPC in AWS using Terraform. The script will do the following:

Create a VPC
Create a Subnet
Create an Internet Gateway
Create a route in the default route table using the Internet Gateway

Contents of main.tf

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
  }
}
 
provider "aws" {
  profile = "tfc"
  region  = "us-west-1"
}
 
resource "aws_vpc" "my-vpc" {
  cidr_block       = "10.0.4.0/24"
  instance_tenancy = "default"
  tags = {
    Name = "my-vpc"
  }
}
 
resource "aws_subnet" "my-subnet" {
  vpc_id            = aws_vpc.my-vpc.id
  cidr_block        = "10.0.4.0/24"
  availability_zone = "us-west-1a"
  tags = {
    Name = "my-subnet-us-west-1a"
  }
}
 
resource "aws_internet_gateway" "my-igw" {
  vpc_id = aws_vpc.my-vpc.id
  tags = {
    Name = "my-internet-gateway"
  }
}
 
resource "aws_default_route_table" "my-rt" {
  default_route_table_id = aws_vpc.my-vpc.default_route_table_id
  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.my-igw.id
  }
  tags = {
    Name = "my-route-table"
  }
}

GCP Spot Instance

November 25, 2021 by Ulysses

You can save anywhere from 60-91% using a spot instance. The downside is, the instance can be preempted anytime.

Create a spot instance.

gcloud beta compute instances create spot-example \
--provisioning-model=SPOT \
--instance-termination-action=STOP \
--image-project=ubuntu-os-cloud \
--image-family=ubuntu-2004-lts \
--machine-type=e2-micro \
--project=your-project-id \
--zone=us-central1-a

Delete instance.

gcloud compute instances delete spot-example \
--project=your-project-id \
--zone=us-central1-a

Terraform AWS Security Group

November 15, 2021 by Ulysses

How to create a security group in AWS via Terraform.

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
  }
}
 
provider "aws" {
  profile = "default"
  region  = "us-east-1"
}
 
resource "aws_security_group" "my_sg" {
  vpc_id       = "vpc-xxxxxxxxxxxxxxxxx"
  name         = "My Security Group"
  description  = "My Security Group"
  ingress {
	from_port   = 8088
	to_port     = 8088
        protocol    = "tcp"
        cidr_blocks = ["0.0.0.0/0"]
  }
  egress {
        from_port   = 0
        to_port     = 0
        protocol    = "-1"
        cidr_blocks = ["0.0.0.0/0"]
  }
  tags = {
        Name = "My Security Group"
  }  
}